Scott Morrison has arrived in Singapore ahead of talks with Lee Hsien Loong on security, trade and a potential travel corridor.
Singapore is the first stop for the prime minister on his way to Cornwall for the G7 leaders' summit, as well as trade and security talks in London and Paris.
Australia already has a COVID-safe travel agreement with New Zealand but a Singapore deal would deliver a confidence boost for the tourism, education and corporate sectors.
It is understood the Singapore government has submitted a number of proposals to Australia, as far back as October last year.
Both countries have rolled out a certificate system to verify who has been vaccinated for coronavirus, which could make a safe travel corridor easier to establish.
Australian officials are hopeful some progress can be made during the leader talks on setting out the preconditions for a travel bubble.
Some countries are setting up travel corridors on the basis of 50 to 60 per cent vaccination rates.
Mr Morrison said international borders would remain shut for as long as was needed to protect health and the economy.
"There's no medical advice that I've received at any point in time, which gives a magical number of vaccinations that enable you to provide that level of assuredness to Australians about when that can occur," he told 6PR radio on Thursday.
Singapore Airlines regional vice president Louis Arul told AAP it was committed to working with all levels of government to reopen Australia's borders.
"Our commitment to Australia throughout this time has been unwavering, supporting the government's efforts to return Australian citizens, facilitating Australian producers and suppliers to export produce ... and ensure the uninterrupted import of essential medical supplies to support the fight against COVID-19," he said.
"We are keen to work with key stakeholders and state and federal governments to progress the safe, staged reopening of borders."
Mr Morrison and Mr Lee will also discuss military training and cooperation and regional security.
At the G7, Mr Morrison will attend three sessions - on health, the economy and climate - and meet with US President Joe Biden, Japanese leader Yoshihide Suga and Korea's Moon Jae-in.
After the summit he'll meet with British PM Boris Johnson in London and hold talks in Paris with French President Emmanuel Macron.
"There has never been a more important time for Australia to be at the table with the world's largest liberal democracies and advanced economies," Mr Morrison said in a statement.
"The global pandemic and the recession it has caused means likeminded counties and businesses need to work together to lead the global recovery to restore lives and livelihoods.
"There is a lot at stake for Australia, the region and the world."
While Mr Morrison is not expected to make any new commitments on climate, Australia is facing calls to support a so-called "carbon border adjustment mechanism" - a levy on the carbon content of emissions-intensive imports.
Mr Morrison said while tackling climate change would be a key issue, other focus areas would be preparedness for future pandemics, business-led growth, free and fair trade and the international rules-based order.
